package service;

/**
 * @author yuzk
 * @date 2018/1/17
 */
public class CalculateService {

    private CalculateService(){

    }
    private static CalculateService service = new CalculateService();

    public static CalculateService getInstance() {
        return service;
    }

    public double add(double a, double b) {
        return a+b;
    }
}
